Attic ventilator



April 7,1942. MacDoUGALD r-:XTER v '2,278,581

'ATTIC- VENTILATOR yFiled Feb. v16, 1940 2 Sheets-Sheet 1 C 7 E A'TTORN; YS

px'il 7, 1942. A vivlewlpouGALD DEXTER ATTIC VENTILATOR 2 Sheets-Sheet 2 l, f l.

Filed Feb. 16, 1940 Patented Apr. 7, 1942 UNITED STAT-,

'FET OFFICE My ,invention relates to a house Ventilating and/or cooling system wherein it is proposed to exhaust the heated or vitiated air near a ceiling, drawing in fresh and cooler air through windows or other openings, and to produce a turbulence .i

throughout the overhead receiving chamber, such as an attic, from which the exhaust 'air escapes through one or more external outlets.

One distinctive feature of my `invention consists in the provision of an overhead room ventilatingopening withv an adjustable damper designed and adapted to cause the converging air currents to flow along under the ceiling radially intoy an annular Ventilating opening, whereby I more effectively cool the room ceiling from below.

A further distinctive feature of my invention is to cause the Ventilating air current, drawn in regulated volume through said overhead opening, to be diiused through the attic by means of a centrifugal fan designed and adapted to ment whereby I both lower and equalize its tem- .perature My invention has as a further distinctive feature the provision of a centrifugal fan of substantial diameter, closed overhead by a top plate comprising a marginal ring of depending impeller blades, running in close coaction with a stationary bottom plate which preferably has its marginal edge extending substantially beyond the fan blades and there upturned slightly to'prevent a back lash of the horizontal radial dispersion of air and to better establish a condition of turbulence throughout the attic.

It is a feature of advantage of my invention that the centrifugal fan used can have a much larger diameter than the ceiling opening and it can be driven with a relatively low R. P. M., and yet have a sufciently high peripheral velocity at the blades to induce the requisite flow of air for Ventilating purposes. The slow rotation re quired in such a construction will eliminate any sound fromthe fan and by using a speed-reduction drive, such as a belt with large and small pulleys, a very small and silent motor can eiectively drive a very large centrifugal fan and induce, at small expense, ample Ventilating air lowand attic air turbulence to'accomplish the objects of my invention. o v

Anothendistinctive feature of my invention has relation to the manner of shutting o the outow. of air through the Ventilating opening by the manipulation. of a counterweighted pendant plate damper whereby the `latter can be itwill permit vthe central disposition of the ventilatingopening in the room without interfering with the center placement of a lighting fixture.

My invention further contemplates the mounting of all moving parts of the ventilator on; a suitableA frame adapted to be set into `the attic and securedvto the ceiling joists over the ventilating opening, sov that skilled labor is not required to set up my Ventilating equpment.-

My invention will be better understoodbyrreference tothe accompanying drawings and detail description that follow, it being understood, however, that the same constitute typical embodiments of my invention. In the` drawings: f n f H l Fig. 1 is a conventional showing of a room and attic in cross section equipped with my improved Ventilating system. with the arrows `indicating the plane' of flow ofthe air currents withfreference to the room ceiling, both above and. below, and the turbulent condition induced in the attic. Fig. 2 is avertical sectional View enlarged, taken on a central plane through the impeller fan, and damperassembly showing-the motor l shown in Fig. 2.

Fig. 4 is a plan View of they damper showing a suspension chain attachment for athin damper plate.

' Fig. 5 is a view of the Ventilating duct and damper shown with a lighting fixture serving as a guide for the damper.

Fig. 6 is a view corresponding to Fig. 5 showing a further modication of the damper carrying a single chain support, with a rigid guide for the chain to hold the damper against vibration.

Similar reference numerals refer to similar parts throughout the drawings.

In the embodiment vof my invention illustrated in Figs. 1 to 4, I show conventionally a room or compartment l0 to be ventilated having a ceiling il with a central ventilator opening I2 therein between the ceiling joists I3-I3. I show the opening I2 as subtending the space between the joists I3 which stand in vertical alignment with the opposed side edges of the opening I2 while the intermediate joist I4 extends centrally across the Ventilating opening. Baiiie plates I5 are set in place between the joists so that they and the joists I 3-I3 enclose a vertical subdivided passageway leading from the Ventilating opening I2 into the attic I6. I mount on top of the joists I3, I4, and on the baiiie plates I5 a bottom plate I1 having an annular central opening I8 (Fig. 3), the diameter of which equals the crosswise dimensions of the rectangular air flue above the Ventilating opening I2. The main body of the plate I1 is horizontally disposed, but about its outer marginal edge it is ared upwardly at I9.

I mount immediately above this plate a centrifugal impeller fan which, as shown, is made up of an annular top 20 having a marginal row of depending, rigidly attached,impeller blades 2 I, connected at their bottom ends to a ring plate 22 disposed to travel in close juxtaposition to the plate I1. The outer periphery of the blades is to set inwardly from the ared edge I9 of the plate I1 and the clearance between the plates I1 and 22 is so close that any back lash of air from the attic to the intake side of the fan is prevented. The plate 20 has a top stiiener plate 23, and a drive shaft 24 for the fan is inserted centrally through the plates 23 and 2U and made fast thereto. The shaft turns in spaced bearings 25 mounted on a cross plate or timber 26, which is preferably long enough to be supported from the joists I3 by means of uprights 21 spiked or otherwise attached to said joists and member.- A grooved pulley 28 is mounted fast on the upper end of shaft 24, and is driven by a V-belt 29 from a smaller grooved wheel pulley 3D driven by an electric motor 3|, pivoted to swing horizontally by its mounting 32a on the plate 26 and having a tension spring 32 connected thereto and to the adjacent upright 21 in position to maintain the requisite tension on the belt 29.

A cross bar 33 extends centrally across the ventilating opening and is made fast at its ends to the plate I1, or to the joists I3, or to both. Idler pulleys 34 are journalled on the side of this bar 33 and a chain 35 passes over the rollers lying between each adjacent pair of joists I3, I4, each chain being connected at one end to a counterweight 36 and at the other end branched, as indicated in Fig. 4, for attachment to elements 31 near the corners of the damper plate 38 that will thus behung free of distortion below, and adapted in raised position to close, the ceiling opening I2. The counterweights will balance the damper plate 38 and thus leave it free for adjustment to any desired working position.

Where a thin light damper plate of substantial area is used it is preferable to dispose the chain attachments 31 near the center of area of each of the four quadrants of the damper as is indicated in Fig. 4, as thereby I equalize the support afforded to the plate and eliminate its distortion'.

In Fig. 6 I illustrate a modified method of support which is applicable to dampers small enough to be suspended by a single support, but which is obviously applicable for use with dampers large enough to require a plurality of such supports. For each support I rigidly attach to the upper surface of the damper plate, adjacent to its respective chain attachment element 31, a tubular guide 40 through which I lead the chain or flexible support 4I for the damper as it passes downwardly from the overhead pulley 42 through the damper to a point below the damper where it carries the counterweight 43. The tubular member is sufliciently elongated to take a purchase against the chain support 4I and restrain the damper from tilting even though suspended from its center by a single hanger chain and guide.

While I prefer the counter-balanced plate damper, because it can be omamentally treated and when closed will look like a decorative center panel in the ceiling, it is to be understood that other types of dampers or closable louvers may be employed.

While I have shown my invention in several forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modicatons, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are speciiically set forth in the appended claim.`

What I claim is:

A Ventilating system for structures, comprising a room to be ventilated having an apertured ceiling and an overhead attic forming a plenum chamber with vents to the outer atmosphere, and a centrifugal suction fan assembly mounted in the attic over the ceiling aperture and comprising a horizontal stationary bottom plate mounted on the ceiling joists with a center opening registering with said aperture to admit air from the room to the attic and having its outer marginal edge upturned slightly away from the top of the ceiling, and a rotatable impeller suction fan having a motor driven top disc carrying marginal dependent blades disposed to travel close to said plate and inwardly from its marginal upturned edge, whereby a dispersion of the induced room Ventilating current throughout the attic is effected to establish therein a turbulent plenum of air with movement over said ceiling to cool its attic side.

MAcDOUGALD DEXTER. 

